HARD SCIENCE ON LYME: Blood Transfusion Risk of Babesia Unacceptable

David Leiby, of the Red Cross, has declared the risk of blood transfusion for Babesia microti to be unacceptably high. Babesia microti is a coinfection of Lyme disease that is transmitted primarily by ticks. Over the past 30 years, between 70-100 cases of transfusion transmitted Babesia have been reported, with at least 12 fatalities. Although the need to screen for the parasite which lives in red blood cells is now recognized as urgent, the method of screening blood has yet to be determined and several obstacles remain before screening practices are adopted. However, according the Leiby, failure to screen is "no longer a viable alternative". The abstract to the article follows the jump. . .

Transfusion-TransmittedBabesiaspp.: Bull’s-Eye onBabesia microti

Summary:Babesiaspp. are intraerythrocytic protozoan parasitesof animals and humans that cause babesiosis, a zoonotic diseasetransmitted primarily by tick vectors. Although a variety ofspecies or types ofBabesiahave been described in the literatureas causing infection in humans, the rodent parasiteBabesiamicrotihas emerged as the focal point of human disease, especiallyin the United States.

Not only hasB. microtibecome establishedas a public health concern, this agent is increasingly beingtransmitted by blood transfusion: estimates suggest that between70 and 100 cases of transfusion-transmittedBabesia(TTB) haveoccurred over the last 30 years. A recent upsurge in TTB casesattributable toB. microti, coupled with at least 12 fatalitiesin transfusion recipients diagnosed with babesiosis, has elevatedTTB to a key policy issue in transfusion medicine.

Despite clarityon a need to mitigate transmission risk, few options are currentlyavailable to prevent the transmission ofB. microtiby bloodtransfusion. Future mitigation efforts may stress serologicalscreening of blood donors in regionalized areas of endemicity,with adjunct nucleic acid testing during the summer months,when acute infections are prevalent. However, several hurdlesremain, including the absence of a licensed blood screeningassay and a thorough cost-benefit analysis of proposed interventions.Despite current obstacles, continued discussion of TTB withoutproactive intervention is no longer a viable alternative.

You can follow additional comments on Lyme policy at www.lymepolicywonk.org.You can contact Lorraine Johnson, JD, MBA at lbjohnson@lymedisease.org.